252 PROCEEDINGS OF THE NATIONAL MUSEUM vol.94 



CETOPSIS COECUTIENS (Lichtenstein) 



Silurus coecutiens Lichtenstein, Wiedemann's Zool. Mag., vol. 1, pt. 3, p. 61, 



1819 (ref. copied). 

 Cetopsis coecutiens Agassiz, in Spix, Selecta genera et species piscium . . . 



Brasiliam . . . , p. 12, tab. 10, fig. 2, and tab. A., fig. 5, 1829 (ref. copied). 

 Cetopsis coecutiens Pellegrin, Bull. Mus. Hist. Nat. Paris, vol. 5, p. 158, 1899 



(Apure River, Venezuela). 



Genus PSEUDOCETOPSIS Bleeker 



Pseudocetopsis Bleeker, Versl. Akad. Amsterdam, vol. 14, p. 403, 1862; Atlas 

 ichthyologique, vol. 2, p. 16, 1862. (T3'pe, Cetopsis gobioides Kner.) 



TENTATIVE KEY TO THE SPECIES OF PSEUDOCETOPSIS 



la. Dorsal rays 1, 5; anal rays about iii or iv, 20 to 23. 

 2a. Head 4 to 4% and depth 4^ to 5}^ in standard length. 



3a. Snout to dorsal origin 2.7 and length of anal base 3.4 in standard length; 

 caudal peduncle longer than deep; maxillary barbel reaching to end of 

 head, posterior m.ental barbel to end of gill membranes under head; 

 maxillary barbel 1.7 in anal base; pelvics reaching to anus; anus a 

 trifle closer to base of caudal than end of snout. 



Pseudocetopsis minutus (Eigenmann) 

 3&. Snout to dorsal origin a little over 3 in standard length; caudal peduncle 



as deep as loKg Pseudocetopsis chalmersi (Norman) 



26. Head 3.2, depth 3.2, snout to dorsal 2.8, all in standard length; snout to 

 dorsal 0.85 in anal base and latter 3.1 in standard length; maxillary 

 barbel reaches halfway to end of head and posterior mental barbel two- 

 thirds way to edge of gill membrances below head; anus much closer to 

 base of caudal fin than to snout tip; branchings of chromatophores 

 parallel or nearly so. [This may be the young of some other species 



already named] Pseudocetopsis macilen.tus (Eigenmann) 



16. Dorsal rays i,6; anal rays iii or iv, 20 to 29; pelvics i,5; head 4 to 4%; depth 4 



to 5J4 in standard length. 



4a. Anal rays about iii or iv, 26 to 29; barbels short, about 3 or 4 times diameter 



of eye and none reaching more than halfway to end of gill membranes; 



pelvics reach to anus; latter about equal distance from caudal base to 



tip of snout or a trifle closer {Pseudocetopsis ventralis (Gill) 



to caudal base jPseudocetcpsis aniphiloxa (Eigenmann) 



46. Anal rays iii or iv, 20 to 24; anus a little closer to base of caudal fin than 

 to tip of snout. 

 5a. Color plain grayish above, paler to silvery below, without dark blotches 

 about size of eye; anal rays iii or iv, 20 to 21; head 4 to 4% and depth 

 4 to 4%. 

 6a. Snout to dorsal origin in anal base 1.1 and 3.2 in standard length; 

 anal base 3 in standard length ; posterior mental barbel reaches half- 

 way to edge of gill membrane below head, and maxillary barbel 

 two-thirds way to end of head; length of maxillary barbel 2.9 in anal 

 fin base; longest rays of both pectoral and dorsal fins about 1.9 in 



snout to dorsal Pseudocetopsis gobioides (Kner) 



66. Snout to dorsal origin 0.8 in anal base and 2.9 in standard length; anal 

 base 3.2 to 3.6 in standard length; posterior mental barbel reaching 

 to edge of gill membranes below head, and maxillary barbel reaching 

 halfway to end of head; maxillary barbel 2.2 in anal base; longest 



